Extrusion head



M. M. SAFFORD EXTRUSION HEAD Oct. 5, 1943.

Filed July l 1941 Invenor: Moyer` M. Safford, by 41M is Attorney vnx'rnusroNHEAT Moyer M. sanare.' Schenectady, N. Y., assimia General aElectric Company, a corporation of `New York Application July 1, 1941, serial'Nc. v4.00.5111 1 claim. (c1. 1s1a) The present invention relates generally to 'exvtrusion devices, and more particularly to an extrusion head for an extruding machine which is useful for covering electrical conductors with plastic insulating material.

Extruding machines generally vused at the present time are of the so-calle'd .side-delivery bent in its course of travel. The extrusion head l type that is, the wire to be covered runs through the extrusion-head of the machine at right angles to the screw or worm which forces the stock through the extrusion head. Such devices require the stock to be turned at -right angles vto its direction of flow 'after leaving the worm in lorder to become parallel tothe wire being' covered. The'turning or bending of the stock is not conducive to even ow, particularly when the stock is fairly still. The result is that there isl a, tendency in this type of extruding machine to produce unevenly covered wire.

In order to overcome this difliculty, so-called straight-through extruaing machines have been manufactured but these machines are much more expensive than the standard side-delivery type and give considerably more trouble due to the l failure of packing glands and other mechanical parts of the machines. In' a straight-through ,jcon'structed chatche stock 1s permitted to flow directly through it without being turned or is designed so that it can be'readily attached by means of the anged collar `2 to a -standard extrusion machine. The stock is fed throughvthe extrusion head by the screw (not shown) of the extrusion machine, being forced through a screen 3 located in an opening 4 at the end of the extrusion head adjacent the extrusion machine. The stock the'n continues through chanl nels 5 toward the extrusion die 6 located at the scribed and claimed in Saord Patent No.

opposite end of the extrusion head. 'Ihe extrusion die 6 may be of the conventional handcentcring type or a lself-centering die as illustrated in,the drawing and more particularly de 2,199,209, of Aprn so, 1940. p

Between thel stock entrance end and the extrusiondic there is provided a lead-in device l for receiving the wire to be covered. This leadin device is removably' attached to -the extrusion delivery machine the wire to becovered runs parallebwith and through the worm and extruding die. Hencethe construction of such a machine requires the provision of a hole through the entire length of the worm. It is also necessary to have the worm so arranged that it can. I. be water-cooled or steam-heated and since. .the

wire goes through 'the 'center of the worm a,

complicated system of glandular packing is required. Moreover, due to the arrangement of porting a pulley il.

parts in such a machine, leader adjustments are difdcult to make due to inaccessihility 'of the parts.

The present invention overcomes the difficulties of the standard side-delivery machine and at thev .same time obviates the complicated structure, of the present type straight-through extruding machine. The invention will be more readily understood by reference to the following description thereof in connection with the accompanying drawing wherein Fig. l is a view`A mainly in section and` partly in elevation oi' an head to facilitate its removal for cleaning or replacement, and fits into a. relatively narrow slot 8 which runs transversely through the central .portion of the extrusion head. The lead-in device l-comprises a base portion 9 having formed integrally therewith a U-shaped element Ill supis provided inthe base portion to' receive the wire I3 which is fed through it from a pay-oi! reel V(not shown). and over the pulley Il through the leader Il, thence to the extrusion die 6. and

out oithe extrusion head to a take-up reel (not shown). As shown 1nthe vdrawing the hollow guide member I2 and the pulley Il are so positioned within the extrusion head' as to provide for the wire tocome in at right angles to the head and then be turned through the leader Il in a direction parallel to thepath of travel of the stock. It' will be seen from the foregoing that a simple, compact structurel has been provided whereby an extrusion lhead is obtained which will fit a standard side-delivery type extrusion machine and at the same time provide for a straight-through travel oi.' the stock without de- I' fleeting it in its course of travel from`the wormthat a simple structure has been provided for.

.extrusion head embodying my invention. Fig.

2 is a. view mainly in elevation/andjpartiy in section of the extrusion head, this view .being at right angles to that of Fig. lgand Fig. 3 is a view in section taken along the line #-3 of Fig. 1.

Referring to the drawing, it -will be seen that the extrusion head, generally designated at I, is

through the extrusion head. It will also be seen bringing the .wireto'be covered into the extrusion head in a?path\ parallel to the direction of travel of the `stock and which, 'by virtue of. its con- -.struction andl arrangement in connection with the, extrusion head,'is easily removed for 'cleaning or replacement.

A hollow guide member I2y While the construction above described is useful for covering electrical conductors with plastic insulation material, it is particularly effective in the coating of such wire of small diameter.

What I claim as new and desire to secureby head .containing a material receiving openingv located at one endof said head, an extrusion die located at the other end of said head and opposite to the material receiving opening', said head containing conveying channels located between the material receiving opening and the extrusion die, a relatively narrow slot extending transversely through the extrusion head, a wire leadin device removably positioned insaid `slot in'- cluding a hollow guide for receiving a wire fed therethrough and a pulley mounted in said leadin device wholly Withinthe slot and positioned to receive the wire from said guide and direct it into the extrusion head to the extrusion die in a path parallel to'the path of travel of the material inthe conveying channels.

MOYER M. SAFFORD. 

